BLUE PLAINS TOUR
April 5, 2019
Earlier this month, members of the LAB team took a field trip – not to any of Washington, DC’s many picturesque locations – but to the Blue Plains sewage treatment plant in Anacostia. This is a remarkable operation. Blue Plains is presently the largest tertiary treatment facility in the world, meaning that nitrogen and phosphorous are removed from the water after the initial settling and biological treatment processes. The plant treats 300 million gallons of wastewater per day, allowing water to return to the Potomac cleaner than it was when it was drawn in above Great Falls. It is also the only sewage treatment facility that processes sludge with steam-driven heat and pressure. This steam process yields a Class A EPA Certified Exceptional Quality biosolid, which is essentially sterile, odorless and extremely rich in plant nutrients. The biosolids were the primary objective for our visit.
LAB has been looking into substituting part of the topsoil in our planting mix with biosolids from Blue Plains. Why? At present, over half of the 22 dump trucks of biosolids produced by the plant is being sent long-distance to farms in central Virginia. Elsewhere, plants are sending their biosolids to landfills. Recently, Blue Plains has been processing its biosolids into ‘Bloom’, a slow release fertilizer for home and commercial use. Specifying ‘Bloom’ would reduce the pressure on landfills and decrease the demand for topsoil stripped from greenfield sites around the city. Our hope is to create a best management practice that could be applied across the landscape industry.
Incorporating biosolids into landscape soils has exciting possibilities for sustainability. First, biosolids seem to have a high potential to produce humus (the nutrient-rich component of soils) as they decompose. Humus adds to the water and nutrient carrying capacity of the soil, AND it permanently sequesters carbon into the soil. What’s more, the biosolids appear to contribute to tilth and fertility when mixed with infertile subsoils. Fostering plant growth without importing topsoil would save money, transportation costs and project schedule while reducing landfilling and topsoil demand - a quintuple-the-word-score play for both ecological and project benefits.
Watch this spot to learn about the results of our research.
Special thanks to our guides: James Fotouhi, a Biosolids and Resource Recovery Technician at Blue Plains and Francesca Valente, Director of Operations for Blue Drop, the non-profit organization tasked with finding markets for Blue Plains biosolids.
The biosolids main process train has a unique piece of infrastructure that uses steam to break down pathogens in the sludge, processing 165,000 tons of biosolids per year.
The LAB team walking through an infrastructural landscape of secondary reactors and wastewater channels.
These channels are pumped with bacteria and air to process the wastewater, an initial step in the refinement that results in ‘Bloom’
One of Blue Plains’ 36 primary sedimentation tanks. The tanks sift out non-biodegradable materials like trash and oils.
The final stop of the tour brought us to the solids processing building where we team members were able to experience (see, smell, and touch) ‘Bloom’ in its final form.
Freshly dewatered “cake” drops off a conveyor belt into a pit of biosolids. Blue Plains produces 22 truckloads each day.